Research has shown that young people with bad spots, called acne, often get it worse when they're worried.

Students were told to write down how bad their spots were before, during and after exam time, and their acne got worse in loads of cases.

Hormones

Skin experts aren't totally sure what causes acne, or what makes it worse, but this research suggests stress is a big factor.

This could be because when we're stressed, our bodies can produce more hormones which can bring out spots.